|
|
|
| Sharma, J., Angelucci, A., Sur, M. Induction of visual orientation modules in auditory cortex Nature 2000 (404):841-847 [pdf] |
| Modules of neurons sharing a common property are a basic organizational feature of mammalian sensory cortex. Primary visual cortex (V1) is characterized by orientation modules groups of cells that share a preferred stimulus orientation which are organized into a highly ordered orientation map. Here we show that in ferrets in which retinal projections are routed into the auditory pathway, visually responsive neurons in `rewired' primary auditory cortex are also organized into orientation modules. The orientation tuning of neurons within these modules is comparable to the tuning of cells in V1 but the orientation map is less orderly. Horizontal connections in rewired cortex are more patchy and periodic than connections in normal auditory cortex, but less so than connections in V1. These data show that afferent activity has a profound inĜuence on diverse components of cortical circuitry, including thalamocortical and local intracortical connections, which are involved in the generation of orientation tuning, and long-range horizontal connections, which are important in creating an orientation map. |
| |
|
|
|
|
|
| Schlaer, R. Shift in binocular disparity causes compensatory change in the cortical structure of kittens Science 1971 (173):638-641 |
| |
|
|
| von Melschner, L., Pallas, S.L., Sur, M. Visual behaviour mediated by retinal projections directed to the auditory pathway Nature 2000 (404):871-876 [html] |
| An unresolved issue in cortical development concerns the relative contributions of intrinsic and extrinsic factors to the functional specification of different cortical areas1-4. Ferrets in which retinal projections are redirected neonatally to the auditory thalamus5 have visually responsive cells in auditory thalamus and cortex, form a retinotopic map in auditory cortex and have visual receptive field properties in auditory cortex that are typical of cells in visual cortex5-8. Here we report that this cross-modal projection and its representation in auditory cortex can mediate visual behaviour. When light stimuli are presented in the portion of the visual field that is 'seen' only by this projection, 'rewired' ferrets respond as though they perceive the stimuli to be visual rather than auditory. Thus the perceptual modality of a neocortical region is instructed to a significant extent by its extrinsic inputs. In addition, gratings of different spatial frequencies can be discriminated by the rewired pathway, although the grating acuity is lower than that of the normal visual pathway. |
| |
|
|
| Hirsch, H., Spinelli, D. Visual experience modifies distribution of horizontally and vertically oriented receptive fields in cats Science 1970 (168):869-871 |
| |
|
|